Evaluation Criteria to Run Scientific Applications in the Cloud - Cloud Computing with e-Science Applications - page 3

SaaS Application

PaaS

IaaS

Datacenter (facilities)

FIGURE 1.1
Service models.

1.2.1 Software as a Service

The software-as-a-service (SaaS) model is commonly used to deliver e-science
services to users. This kind of portal is used to run standard scientific appli-
cations, and no customization is allowed. Normally, a provider ports an
application to its cloud environment and then provides access for the users to
use the applications on a regular pay-per-use model. The user of this model
is the end user, such as a biologist, and there is usually no need to modify
the application.
One example of a provider porting a scientific application and then pro-
viding the service to the community is the Azure BLAST [2] project. In this
project, Microsoft ports the Basic Local Alignment Search Tool (BLAST) of the
National Center for Biotechnology Information (NCBI) to Windows Azure.
BLAST is a suite of programs used by bioinformatics laboratories to ana-
lyze genomics data. Another case of this use are the Cyclone Applications,
which consist of twenty applications offered as a service by Silicon Graphics
Incorporated (SGI). SGI provides a broad range of applications that cover sev-
eral research topics, but there is no possibility to customize and adapt them.
The big problem with SaaS as the environment to build e-science services
is the absence of the ability for customization. Research groups are con-
stantly improving their applications, adding new features, or improving
their performance, and they need an environment to deliver the modifica-
tions. In addition, there are several applications that are used for only a few
research groups, and this kind of application does not attract the interest
of the cloud providers to port them. In this case, this model can be used to
deliver an e-science service but not as an environment to build it.